Amount of food?

Hello all! I am a chin mommy of two boys, Fred and George. They are just over a year old and are always very very hungry. I have been following the 2 tbs pellets and unlimited hay diet that was suggested to me, but I was wondering if it's safe to feed them more pellets than that?

I was told unlimited pellets/hay until they are one year old and then to start measuring out the pellets. Any advice would be great! Thanks :)